Q: When would you use AOI off-line instead of in-line?
LaMarche: /b>Off-line AOI is excellent for first-article inspection and optimizing the manufacturing process. Because it’s off-line, it does not disrupt manufacturing flow, which maximizes utilization of the production line. In addition, off-line AOI is perfect for low-volume or prototype manufacturing. In-line AOI equipment is typically not available for this level of production. However, the need to ensure that all parts are present still exists. The key concern for most manufacturers is whether all of the components have been placed. Are they actually there? This cannot be determined through visual inspection by an operator. The off-line AOI can provide this.
Q: Where on the line is the best place to use AOI?
LaMarche: /b>AOI is a powerful technology for checking the presence or absence of solder paste; for checking the presence or absence of components prior to reflow; for performing optical character recognition; and for inspecting solder attachments after reflow. I believe AOI is best-utilized as a pre-reflow inspection tool. It is at this point that the key quality issues will arise. Most manufacturers have a high level of confidence in their pick-and-place systems. They just need to know if all of the parts placed correctly before they begin full-out production.